1. Field of the Invention
This invention relates to methods for forming a projection on a conductor, and for stripping an insulation covering from the conductor; and, more particularly, to methods for forming one or more projections at an interconnection area along an elongated insulated conductor, and for removing the insulation from the conductor at the interconnection area.
2. Description of the Prior Art
It is known to employ electrical conductors, such as plural, parallel-extending, conductive paths in a flat flexible cable, in which interconnection areas along one or more conductive paths include projections extending transversely to a major portion of the conductive path or paths. Such projections serve to facilitate the interconnection, e.g., by soldering, of additional conductors or terminals, one at each such area. Any insulation is, of course, stripped at the areas selected for interconnection. Some examples of the described conductor structures are disclosed in U.S. Pat. Nos. 782,391 to A. P. Hanson; 1,054,784 and 1,104,061, both to F. R. McBerty; 2,433,346 to G. Deakin; 3,197,555 to S. Mittler; and 3,615,283 to D. D. Lang.
A technique for forming a projection at an interconnection area along a conductor, at which interconnection area an insulation covering, extending over other areas along the conductor, is removed, is disclosed in U.S. Pat. No. 1,801,311 to G. T. Johnson. The Johnson patent reveals a pair of rotary members which include cooperating male and female die portions in the respective rotary members. As the two rotary members are rotated, an insulated wire is fed between them, the die portions on the rotary members functioning to form the desired projections in the insulated wire. The cooperative action between the mating die portions is effective also to strip the insulation from the wire about the projections.
The Johnson technique appears adequate for the forming of projections in, and the stripping of, a single insulated wire. However, the technique is not well suited for use in operating on plural conductor structures, such as flat flexible cable, where various interconnection areas at different axial positions along different conductive paths may be involved. Any such use of cooperating male and female die portions on a pair of rotary members, in processing conventional types of flat flexible cable, would tend to result in fracture of the cable insulation not only in the vicinity of a projection formed in a single conductive path at which stripping is desired, but also extending laterally across the cable to one or more additional conductive paths, and, perhaps, all of the conductive paths. Such additional fracture of the cable insulation, even if not occurring during the forming and stripping operation, would likely take place during subsequent processing or use of the cable. An improved technique for forming projections in, and stripping insulation from, interconnection areas along conductors, better suited to use in operating on conventional types of flat flexible cable, would clearly be advantageous.